The element rhenium (Re) exists as two stable isotopes and 18 unstable isotopes. Rhenium-185 has in its nucleus
1 answer:
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Answer:
See the image 1
Explanation:
If you look carefully at the progress of the SN2 reaction, you will realize something very important about the outcome. The nucleophile, being an electron-rich species, must attack the electrophilic carbon from the back side relative to the location of the leaving group. Approach from the front side simply doesn't work: the leaving group - which is also an electron-rich group - blocks the way. (see image 2)
The result of this backside attack is that the stereochemical configuration at the central carbon inverts as the reaction proceeds. In a sense, the molecule is turned inside out. At the transition state, the electrophilic carbon and the three 'R' substituents all lie on the same plane. (see image 3)
What this means is that SN2 reactions whether enzyme catalyzed or not, are inherently stereoselective: when the substitution takes place at a stereocenter, we can confidently predict the stereochemical configuration of the product.
The correct answer is option C, 5.02 x 10²² carbon atoms
Atomic mass of C = 12 g/mol
According to Avogadro, 1 mole of C has 6.023 x 10²³C atoms
Now 1 mole of C is equal to 12 g
Therefore, 12 g of C = 6.023 x 10²³ C atoms
1 g of C = C atoms = 5.02 x 10²² C atoms